Refractory bottom for metallurgical furnaces



w. R. mum 2,423,898

REFRACTORY BOTTOI FOR IBTALLURGICAL FURNACES Filed Feb. 18, 1944 July15', 1947.

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IV/um! P5X TTORNEY Patented July 15, 1947- REFRACTORY BOTTOM FORMETALLURGICAL FURNACES William lie: McLain, Chicago, Ill., assignor toCarnegie-Illinois Steel Corporation, a corporation of New JerseyApplication February 18, 1944, Serial No. 522,948 I This inventionrelates to furnace bottoms, and particularly to an improved refractorybottom for the hearth of metallurgical furnaces, such as blast furnacesand the like.

The bottom for the hearth of blast furnaces and other similarmetallurgical furnaces is made generally of standard brick shapes offire clay,

usually rectangular parallelepipeds. In a blast furnace bottom, thebrick work consistsgenerally of a plurality of courses of fire brickswhich are disposed in staggered relation so as to provide a solid bottomfrom approximately 9 to 12' feet thick and from 25 to 30 feet indiameter. Heretofore, the brick work was usually installed by cutting orrounding the outer sides of'the outermost bricks next to the watercooled hearth jacket so that the same would fit tightly thereagainst.The hearth jacket is usually shaped like the frustum of a cone,v andthus considerable cutting of the outer bricks was necessary in order toobtain a good fit. It will be seen that such procedure was not onlylaborious but tedious and expensive.

Also, if the outer bricks of the bottom do not abut firmly against thewater cooled jacket. the full cooling effect of the hearth jacket is.not realized because any air spaces between the outer bricks and thewater cooled jacket are not good conductors of heat. In other words, insuch a case the heat in the center of the. hearth was not transmittedrapidly enough to the water cooled jacket and the metal collects on thecenter of the bottom of the hearth tending to erode and replace thebricks therein with a solid mass of metal which is known as thesalamander. Such a condition consequently makes the bottom of less depthand increases the danger of molten metal breakouts through the furnacebottom.

Accordingly, it is one of the objectsof the present invention to providearr-improved refractory bottom for blast furnaces and the like whereinstandard fire brick is used and cuttingof the outer sides of the outerbricks of the bottom is eliminated thereby reducing maintenance andreplacement costs to aminimum. 4

It is another object of the invention to provide an improved refractorybottom for blast furnaces 2 Claims. (Cl. 266-43) and the like whereinthe bottom is continuous from the center of the bottom to the watercooled jacket therearound thereby insuring an effective and rapidtransmission of heat from the center of the bottom to the water cooledjacket so as to prevent the formation of an\ excessive salamander.

It is a further object of this invention to protom for blast furnacesand the like having a center portion of standard brick shapes and anouter portion adjacent the water cooled hearth jacket, of a relativelyhigh heat conducting refractory rammed into place between the fire brickand the cooling jacket so as to entirely fill the space therebetweenthereby eliminating any voids.

Various other objects and advantages of this invention will be moreapparent in the course of the following specification and will beparticularly pointed out in the appended claims.

In the accompanying drawings there is shown, for the purpose ofillustration, an embodiment which my invention may assume in practice.

In these drawings:

Figure 1 is a vertical section through the hearth of a blast furnaceshowing the improved refractory bottom of my invention incorporatedtherewith; and

Figure 2 is a sectional view taken on line IIII of Figure 1.

Referring more particularly to the drawings, there is shown the lowerportion of the hearth of a blast furnace comprising a bottom 2 and aside wall 3 having a water cooled jacket 4 circumferentially arrangedtherearound. The bottom 2 and the cooling jacket 4 rest preferably on asuitable concrete base 5 in a manner well known to those skilled in theart.

According to the present invention, the center portion of the bottom 2consists of a plurality of courses of fire bricks 6 which are disposedin staggered relation so as to provide a solid center column of brickwork. The fire bricks 6 are preferably standard brick-shapes, or brickshapes of fire clay. The brick work of the center portion fillssubstantially the space within the inner periphery of the water jacket4, as shown in Figure 2 of the drawing. However, it will be seen thereis disposed a refractory material I which fills entirely the spacetherebetween so as to eliminate any voids between the outer side of thecolumn of brick work and the water Jacket. It isimportant that therefractory material used have terials are preferable so that therefractory will not flux the adjacent firebrick S; Refractories mostsuitable for use are graphite, amorphous carbon, coke, or any otherhighly carbonaceous material, or a combination thereof, mixed with up toapproximately 97 per cent of a suitable bonding material, such as flreclay, bentonite, hot tar, or any other similar material or any of theorganic bonds. Also, 'magnesite-cement, or magnesite clay mixtures aresuitable refractories rammed into place.

It has been found that a mixture having good heat conducting propertiesand also'one which may be easily rammed into place, i. e., goodworkability. consists of approximately 40 per cent fire clay and 60 percent graphite crushed to pass a 4 mesh U. 8. standard sieve. It has beenfound also that a mixture of one part of hot tar, six parts of graphite,or amorphous carbon, or coke, or other highly carbonaceous material, ora combination thereof provides a satisfactoryrefractory for such use. Itis important that the amount of graphite in the mixture be sufiicientlyhigh so that the mixture will have a coefllcient of heat.

conductivity at least equal to the fire clay brick 6. It will beunderstood that any combination of a refractory gregate and a bondingagent which will provide a relatively high coefllcient of heatconductivity equal to or greater than the standard fire brick 6 used forthe center portion of the bottom and which will not flux therewith canbe conveniently used in the practice of this invention.

When installing the bottom of the present invention, it will beunderstood that the bricks 6 are laid as in the standard practice exceptthat enough space is provided between the center.column of brick workand the water cooled hearth jacket so-asto permit the pla insand ra inof the refractory material I therebetween. It is preferable that therefractory material be placed between the brick work and the coolingjacket after each course of brick work is laid. However, the refractorymay be placed between the brick work and the cooling jacket after all ofthe courses of brick work have been laid, but under such circumstancesit is necessary to insure that the refractory is properly rammed intoplace at all courses in the brick work so as to eliminate the danger ofany spaces or voids being left between the brick work and the waterjacket.

As a result of my invention, it will be seen that it is not necessary tocut the outer sides of the outermost bricks 6 so that they flt tightlyand possess the characteristic ofbeingeaslly against the inner peripheryof the water cooled jacket 4. In other words, standard brick shapes maybe used, thus eliminating the cutting thereof. Also, it will be seenthat by using the improved bottom of my invention, that the heat towhich the center of the bottom is subjected will be rapidly transmittedfrom the brick work 8' through the refractory I to the water cooledJacket 4 thereby tending to prevent the formation of an excessivesalamander in the center portion of the furnace bottom.

While I have shown and described a specific I embodiment of myinvention, it will be understood that this embodiment is merely for thepurpose of illustration and description and that various other forms maybe devised within the scope of my invention, as defined in the appendedclaims.

I claim:

1. A bottom for the hearth of blast furnaces and the like having a watercooled hearth jacket arranged therearound comprising a center portionmade of a plurality of courses of fire brick, and an outer portionarranged between said fire brick and the water cooled jacket made of arefractory material which is rammed into place therebetween having acoefficient of heat conducitivity at least as great as that of the firebrick, aid refractory material adapted to transmit rapidly the intenseheat to which the center portion of the bottom is subjected to the watercooled jacket, thereby tending to prevent the formation of a salamanderin the bottom of the furnace.

2. A bottom for the hearth of blast furnaces having .a water-cooledjacket arranged therearound comprising a center portion made of aplurality of courses of fire brick, and an outer portion arrangedbetween said fire brick and the water-cooled jacket made of a refractorymaterial, which will not flux the fire brick at smelting temperatures,and which is rammed into place therebetween, said refractory materialconsisting of a finely crushed mixture of a bonding material such asfire clay and suificient carbonaceous material to provide a coefficientof heat conductivity at least as great as that of fire brick. wherebysaid refractory material will rapidly transmit heat away from saidbricks thereby tending to prevent the formation of a salamander in thebottom of the furnace.

- WILLIAM REX McLAIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,256,179 Thomson Sept. 16, 19411,777,617 Jack Oct. 7, 1930

